1. Field of the Invention
This invention relates generally to gas turbines, and more particularly, to seals between stator shrouds in the gas turbines.
2. Description of the Prior Art
In axial flow gas turbines, the stator vanes are mounted in a group. They are held in this group by an arcuate shroud member on both their radially inner and their radially outer ends. The shrouds, when adapted to the turbine, form an annular array of support members for the vanes.
A gap exists between adjacent shrouds. The gap permits thermal expansion of the shrouds, and prevents the shrouds from buckling. The gap also, however permits leakage of hot working fluid from the hot working flow path. Turbines have been designed with shrouds that have an overlap between adjacent end portions of the shrouds, or with a tongue and groove seal arrangement. These designs have their limitations, because they allow either a radial or an axial leakage of fluid. A buckling or interference can occur between the shrouds, if the gap is too narrow, or if there is a mismatch or misalignment in the assembly of the shrouds. The present invention helps overcome these objections to the prior art.